Id say your looking at $3-5000 to make it look cosmetically like an SRT8. The V6 sounding like the V8 will be a little tougher. The best I have heard IMO is Timmyb's exhaust, he followed my how to....took an full SRT exhaust, removed the suitcase muffler, added a Y pipe and then had it installed. There is a how to in the how to forum

I personally am not a fan of making a V6 look like an SRT8. At least start with a 4.7 V8 so it can have a decent exhaust. If not its all show no go. You can make any wk look like an SRT but you will never get the performance of a true SRT with just a body kit and you will never be able to show it off like and srt8 either.